Comparative analysis of ovine adenovirus 287 and human adenovirus 2 and 5 based on their codon usage.

Ovine adenovirus 287 (OAdV287) emerges as one of the most promising gene vectors resulting from its unique biological characteristics. To obtain a more detailed knowledge about the codon usage of OAdV287, a comparative study based on the codon usage of OAdV287 and the prototypes of human adenovirus serotypes 2 and 5 (HAdV2/5) was carried out. Some commonly used indices measuring the codon usage patterns, including effective number of codons, relative synonymous codon usage, and statistical methods, were adopted. Overall, OAdV287 had a more biased and conservative codon usage pattern than that of HAdV2/5. Both mutation pressure and natural selection played important roles in shaping the codon usage patterns of these three adenoviruses. All the preference codons of OAdV287 had A/U ends and were totally different from those of sheep and humans; however, the preference codons of HAdV2/5 mostly had G/C ends and were mostly coincident with those of sheep and humans. The codon usage analysis in this study supplies some clues for further comprehending the unique biological characteristics of OAdV287 as gene vectors.